I wonder what happens when you ping 127.0.0.1... I never tried it

You ping your own machine.

I will exclude reserved addresses from the scan. This includes the entire 127.x.x.x range as well.

Make sure to exclude all IPs in the ranges listed here: http://en.wikipedia.org/wiki/IPv4#Special-use_addresses

You get a really fast reply.

Quote from: DJ Omnimaga on September 24, 2014, 08:03:02 pm

I wonder what happens when you ping 127.0.0.1... I never tried it

You get very fast replies

Replies so fast it's almost instant.

juju@derpy ~ % ping 127.0.0.1
PING 127.0.0.1 (127.0.0.1) 56(84) bytes of data.
64 bytes from 127.0.0.1: icmp_seq=1 ttl=64 time=0.026 ms
64 bytes from 127.0.0.1: icmp_seq=2 ttl=64 time=0.043 ms
64 bytes from 127.0.0.1: icmp_seq=3 ttl=64 time=0.044 ms
64 bytes from 127.0.0.1: icmp_seq=4 ttl=64 time=0.044 ms
^C
--- 127.0.0.1 ping statistics ---
4 packets transmitted, 4 received, 0% packet loss, time 3000ms
rtt min/avg/max/mdev = 0.026/0.039/0.044/0.008 ms

During that time, light have time to travel about 8-13 km (5-8 miles). Which is not quite enough to reach another computer, if you take in account the time the other computer takes to notice your ping and send a reply.